Re: Road Noise

[Bill Wilson <us733@xxxxxxxxxxxxxxxxxxxxxx>]

On Thu, 25 Sep 1997, David Staudacher wrote:

> On Tue, 23 Sep 1997 13:48:40 -0700, 
> Christopher England   <cengland@earthlink.net> wrote:
> 
> >But freeway noise rumbles through most of LA.  The noise bounces off
> >clouds, gets bent by inversion layers; its all over.  Nobody knows that
> >it can be controlled.  QUIETER TIRES!
> 
>    How can you make a tire more quiet?  Is it a different rubber 
> formula?  Different tread design?  
> 
>    I think the kind of road surface can make a lot of difference 
> too.  Often when I'm on a freeway I notice how the sound can change 
> dramatically according to the type of road surface changes.  The 
> noisiest always seems to be the standard grey concrete style.  I have 
> seen red-ish looking surfaces that are somewhat quieter.  Country 
> two-lane blacktop always seems to have a low, rumbling quality.
> 

Unfortunately, I didn't receive Chris England's origional post but from 
what was quoted I think the type of tires are the noisier of the two 
contacting surfaces. Tread is the culprit. I travel exclusively by 
bicycle, and with both motor vehicles and bicycles have observed a direct 
relationship between the aggressiveness of the tread the noise they 
produce.

Some years ago, Victoria hosted a Calming Cascadia conference on traffic 
calming, which I attended. Apparently there is an exponential relationship
bewteen the speed of the vehicle and the noise it produces, small reductions
in speed can result in larger reductions in noise. The relationship also
holds for the emissions, if you're close enough to hear the noise you're 
probably also being affected by those emissions, both of which can be 
reduced by lowering the speed limit. 

 
and